Author Topic: Real size map or UVW !  (Read 850 times)

2023-02-15, 14:04:31

Yousef13

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Hello

So it has been 14 months since I started learning 3dmax and corona, and I have always apply materials to objects then apply UVW map modifier on them and set the size of the map to the size I see close to reality, like this : https://ibb.co/KywRGNX


I was watching a tutorial in YT where they done it differently, they gave the map a real world size and apply UVW modifier and set it to box then checked real world size. see here : https://ibb.co/9Yn6kXp


So now I am excited to use this method cause it seems better, because I only need to add one UVW Map to an obecjt even if I have 3 or 4 materials

So I am here telling you this because I have a feeling someone would explain to me why the easiest method ( the second ) is wrong or something like that, I can't believe all courses I took and tutorials I have watched have not mentioned that, or they have but I was focusing on my first method
Or maybe someone would point me to a better way ?
Also, when I buy a map like fingerprints or dirt, why don't they give real world size so we can apply it ? I find this confusing even with some albedo maps, eventually I will set it to how I see fit but I am just wondering!
Thank you

2023-02-15, 16:17:17
Reply #1

James Vella

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If you work in architecture then real-world mapping is the way to go in my opinion. It saves you countless hours over the years when you have set up your materials as per the size you require. Also if you have other textures that use similar parameters (tiles for example) then when you create these textures you have a reference size/resolution.

I guess because whoever authored the fingerprint texture didn't take the resolution/real-world size into account or maybe doesn't apply to their situation. You could also contact the author and ask I suppose.

edit:
Quote
So now I am excited to use this method cause it seems better, because I only need to add one UVW Map to an obecjt even if I have 3 or 4 materials
Then this is really going to blow you socks off :)
Customize > Preferences > Texture Coordinates > Use Real-World Texture Coordinates. Have fun :)
« Last Edit: 2023-02-15, 16:28:24 by James Vella »

2023-02-15, 16:24:50
Reply #2

romullus

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Both methods are correct and you can choose which one to use basing on situation and your personal preferences. You can even mix them in the same scene and in the same material. even more, it's ok to use RW texture on a non RW mapped object and vice versa. In fact both mapping methods are essentially the same, the only difference is that with RW mapping the scale is managed automatically. And that's it. RW mapping is very useful in archviz where the same tiling texture must be mapped on multiple objects of different sizes and proportions - you simply don't need to worry about the scale. On the other hand it won't work on objects unwrapped to 0-1 UV space that uses bespoke non-tiling textures.

Also, when I buy a map like fingerprints or dirt, why don't they give real world size so we can apply it ? I find this confusing even with some albedo maps, eventually I will set it to how I see fit but I am just wondering!

In many cases real texture scale doesn't matter much (your mentioned fingerprints and dirt exactly falls into that category), in other cases vendors simply don't know, or don't care to give real world scale. Serious assets providers like Megascan will always provide scale information with their assets, along with other useful info.
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2023-02-15, 16:30:17
Reply #3

James Vella

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On the other hand it won't work on objects unwrapped to 0-1 UV space that uses bespoke non-tiling textures.

Yes good point, in that case the option I provided under the quote would give you headaches since you have to do the reverse for all objects you apply textures to (in the texture and the uvw modifier).

edit:
Thinking about this more, probably not actually since bespoke textured items are usually purchased assets like furniture and don't need remapping, only color corrections or swap-outs which you can do on an individual basis. Generally I find building the set much faster with real-world so use the information provided as you wish, do some of your own testing and see what works best for you. I change this depending on the work I'm doing so if it works for your situation then great, if not change it.
« Last Edit: 2023-02-15, 16:43:05 by James Vella »

2023-02-15, 16:57:50
Reply #4

romullus

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edit:
Thinking about this more, probably not actually since bespoke textured items are usually purchased assets like furniture and don't need remapping, only color corrections or swap-outs which you can do on an individual basis. Generally I find building the set much faster with real-world so use the information provided as you wish, do some of your own testing and see what works best for you. I change this depending on the work I'm doing so if it works for your situation then great, if not change it.

Sure thing, i was simply providing typical usage cases, but as i mentioned earlier, those mapping methods are not mutually exclusive, you can easily replace one with another if you wish. Again, all that information is aimed mostly at OP - i have no doubts about your knowledge :]
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2023-02-15, 19:08:08
Reply #5

James Vella

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Sure thing, i was simply providing typical usage cases, but as i mentioned earlier, those mapping methods are not mutually exclusive, you can easily replace one with another if you wish.

Yes you are absolutely right, I'm glad you included the other use cases.

I was responding to my own comment when I started thinking more about how I work with assets and how I set up scenes in archviz lol. So yes, totally agree!

2023-02-16, 00:34:13
Reply #6

Yousef13

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If you work in architecture then real-world mapping is the way to go in my opinion. It saves you countless hours over the years when you have set up your materials as per the size you require. Also if you have other textures that use similar parameters (tiles for example) then when you create these textures you have a reference size/resolution.

I guess because whoever authored the fingerprint texture didn't take the resolution/real-world size into account or maybe doesn't apply to their situation. You could also contact the author and ask I suppose.

edit:
Quote
So now I am excited to use this method cause it seems better, because I only need to add one UVW Map to an obecjt even if I have 3 or 4 materials
Then this is really going to blow you socks off :)
Customize > Preferences > Texture Coordinates > Use Real-World Texture Coordinates. Have fun :)

what does this option do ? I only make materials for walls, closets, tables, kitchens, doors ..etc only simple models that I do myself, when it comes to sofas and chair or other complicated models, I just buy and use them as they are, only changing the hue and saturation If I need. < I tried to understand unwrapping once, I couldn't so your discution with romullus is above my level   :D

Thank you

Both methods are correct and you can choose which one to use basing on situation and your personal preferences. You can even mix them in the same scene and in the same material. even more, it's ok to use RW texture on a non RW mapped object and vice versa. In fact both mapping methods are essentially the same, the only difference is that with RW mapping the scale is managed automatically. And that's it. RW mapping is very useful in archviz where the same tiling texture must be mapped on multiple objects of different sizes and proportions - you simply don't need to worry about the scale. On the other hand it won't work on objects unwrapped to 0-1 UV space that uses bespoke non-tiling textures.

Also, when I buy a map like fingerprints or dirt, why don't they give real world size so we can apply it ? I find this confusing even with some albedo maps, eventually I will set it to how I see fit but I am just wondering!

In many cases real texture scale doesn't matter much (your mentioned fingerprints and dirt exactly falls into that category), in other cases vendors simply don't know, or don't care to give real world scale. Serious assets providers like Megascan will always provide scale information with their assets, along with other useful info.

I will use real world size from now on, much faster in my case.
I only do archviz, so a fingerprint on a glass has to be the right size and it would be great if knew exactly the size instead of eyeballing it.
--

https://ibb.co/G76GWR2
I get this result by selecting the horizontal faces and apply another UVW map then rotate, is there a better way ?
I don't understand corona Triplanar map, how can I use it to my advantage in simple interior scnenes ?

2023-02-16, 07:44:04
Reply #7

James Vella

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what does this option do ?

Enabling this means that your bitmaps and uvw modifier use real-world settings by default so you don't have to manually turn them on every time you import the bitmap or apply the modifier. Saves you a few clicks I suppose, I would still use box instead of planar mapping but handy regardless.



Also when creating/extruding shapes by default it enables real-world mapping so you dont need to even apply the UVW modifier. Same goes when creating Boxes/Spheres etc.



Quote
https://ibb.co/G76GWR2
I get this result by selecting the horizontal faces and apply another UVW map then rotate, is there a better way ?

If its one piece of geometry then rotating it that way is probably quick enough. If you are making these components separately with boxes/shapes when building the cabinets etc then it does depend on the viewport you create it. For example this is when I create a box in top view, all edges are aligned automatically the correct direction.



This is creating the object in front view, now I have to select the edge faces to rotate them. This technique applies to many things in 3dsmax like when doing sweeps/lofts etc.



Quote
I don't understand corona Triplanar map, how can I use it to my advantage in simple interior scenes ?

romullus could probably answer this one better since I don't really use it much these days however as far as I'm aware you can also do mapping with it by rotating the axis within the material instead of doing it for each face like you requested (without needing multiple uvw maps). It also has other features like blending to removing visual tiling etc. You can watch a few videos about it Corona has online for different use cases as well.

Example of using the Corona Triplanar with only 1 uvw map. Default settings


Then if you enable disable "use map X for all axes" and rotate the W:90 in the Z axes you have the expected behavior (or use the Rotate settings in the bottom Rollout and keep use map for X for all axes enabled for a faster workflow)


The main benefit really by using the Realworld mapping option means that in the long run once you save all your materials to a library you are basically just creating shapes/extruding, slapping on the materials and you always know it will be the correct scale and/or direction so you dont need modifiers, dont need to double check scale etc.

If you really want to get technical later on you can do as I said earlier about the tile reference - meaning when you author textures you can create them at the correct scale before going in 3D so making sure all the wood grain is correct for that texture resolution etc, making sure your tiles are exactly 60x60cm etc. Then when you apply these in 3D using your saved library as a base for your new material you already know those tiles/wood grain will be the correct scale. You can really move at a fast pace if doing lots of Set work.
« Last Edit: 2023-02-16, 08:00:46 by James Vella »

2023-02-16, 16:19:56
Reply #8

romullus

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I get this result by selecting the horizontal faces and apply another UVW map then rotate, is there a better way ?

James Vella already explained everything, i just add one more way how to quickly edit UVW mapping on selected faces. First you need to go to polygon sub-object mode, select all the faces that you need to alter, add UVW xform modifier on top and rotate, tile, or offset UV coordinates. As long as apply to entire mesh checkbox is inactive, the modifier will only affect UVs of selected faces.
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2023-02-16, 20:04:15
Reply #9

Yousef13

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Enabling this means that your bitmaps and uvw modifier use real-world settings by default so you don't have to manually turn them on every time you import the bitmap or apply the modifier. Saves you a few clicks I suppose, I would still use box instead of planar mapping but handy regardless.

Quote
Also when creating/extruding shapes by default it enables real-world mapping so you dont need to even apply the UVW modifier. Same goes when creating Boxes/Spheres etc.

I checked the option and it works as you said, except when I extrude a polygon of a box the map stretch and I have to apply uvw modifier, is it supposed to be like that even after checking the real-world coordinates option?

Quote
This is creating the object in front view, now I have to select the edge faces to rotate them. This technique applies to many things in 3dsmax like when doing sweeps/lofts etc.

that's very good know, I always that the software is acting up when this happen to me :D

Quote
The main benefit really by using the Realworld mapping option means that in the long run once you save all your materials to a library you are basically just creating shapes/extruding, slapping on the materials and you always know it will be the correct scale and/or direction so you dont need modifiers, dont need to double check scale etc.

Yes I already started modifing my library :d
Thank you for your help, I learnt so much

 

2023-02-16, 20:05:44
Reply #10

Yousef13

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https://ibb.co/G76GWR2
I get this result by selecting the horizontal faces and apply another UVW map then rotate, is there a better way ?

James Vella already explained everything, i just add one more way how to quickly edit UVW mapping on selected faces. First you need to go to polygon sub-object mode, select all the faces that you need to alter, add UVW xform modifier on top and rotate, tile, or offset UV coordinates. As long as apply to entire mesh checkbox is inactive, the modifier will only affect UVs of selected faces.


That's really helpful, never used UVW xform before
Thank you so much guys

2023-02-16, 20:54:40
Reply #11

James Vella

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I checked the option and it works as you said, except when I extrude a polygon of a box the map stretch and I have to apply uvw modifier, is it supposed to be like that even after checking the real-world coordinates option?

If you extrude using a modifier (shape/spline) you can keep real-world coordinates.

If you extrude using a polygon you need to use a UVW modifier, since it stretches' the UV.

I dont really know a good way to explain it but probably the most universal way to think about it is like this:
If I have a shape or box made from 3dsmax it understands the dimensions thus can understand the proportions of the UV by calculating it mathematically. When you extrude via a polygon it doesnt calculate by how much you extruded by. Houdini has this kind of capability because it stores all this data node by node, or step by step. In my understanding when you extrude in 3dsmax there is nothing stored in data so it can be 30cm or 30px or whatever but there is no measurement stored in edit poly mode - thus it doesnt really understand what you are trying to accomplish. By applying the real-world UVW modifier it just say so ok whatever changes you make its just going to calculate every pixel/cm by this much and apply the same dimensions for the UVW down the layer stack. There could be ways to work around this with 3dsmax scripts but its simple just using a real-world modifier in this case.

Another way to think about it is a layer system vs a node system. The modifier stack works like a layer system, so whatever changes you make in the edit poly layer disregards the layer below it (the UVW). So if I extrude a polygon then it stretches because the layer below (UVW real-world) is stretched on this layer (edit poly). When I apply a UVW real-world above the edit poly layer it says ok anything below this layer (edit poly) ignore that UVW and now apply the real-world UVW.

Also take into consideration what romullus said about "selected polygons" you can negate layers in the stack with selected polygons, well kind of opposite. Meaning if you have a bunch of selected polygons the next layer up (modifier) can affect only those selected polygons/faces/edges. If you then deselect all polygons you can apply to everything, its very flexible but try these things with simple boxes and shapes to work out what is going on before you start layering things like a mad man as the "masks" are not as visible as they are in photoshop once you are a few modifiers deep for example.
« Last Edit: 2023-02-16, 21:50:01 by James Vella »